Posterior vertebral plating system

ABSTRACT

A posterior vertebral plating system comprising a plate and a plurality of attachment members. The plate has a plurality of holes extending through the plate from an upper surface to a lower surface, and the plate is configured to extend along the posterior side of at least two vertebrae adjacent at least one boney structure of each of the vertebrae. The holes are spaced in such a way that a first plurality of holes is positionable over a boney structure of a first vertebra to define a plurality of fixation points to the first vertebra and a second plurality of holes is positionable over boney structure of a second vertebra to define a plurality of fixation points to the second vertebra. The attachment members are insertable through the holes of the plate and into the boney structure of a corresponding vertebra to fix the plate to the vertebra.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/491,769, filed Sep. 19, 2014, which is a continuation of U.S.application Ser. No. 13/437,792, filed Apr. 2, 2012, now U.S. Pat. No.8,845,697, which claims priority to U.S. Provisional Application Ser.No. 61/470,821, filed Apr. 1, 2011, the entirety of each of which beinghereby expressly incorporated herein by reference.

BACKGROUND

The spinal column of bones is highly complex in that it includes overtwenty bones coupled to one another so as to house and protect criticalelements of the nervous system. In addition, the spine is a highlyflexible structure, capable of a high degree of curvature and twist inmultiple directions. The most flexible of all the regions of the spinalcolumn is the cervical spine.

The bones and connective tissue of an adult human spinal column arecoupled sequentially to one another by a tri-joint complex whichconsists of an anterior disc and the two posterior facet joints. Theanterior discs of adjacent bones are separated and cushioned bycartilage spacers referred to as intervertebral discs. The vertebralbones of the spine are classified as cervical, thoracic, lumbar, andsacral. The cervical portion of the spine, which comprises the upperportion of the spine up to the base of the skull, includes the firstseven vertebrae. The twelve intermediate bones comprise the thoracicvertebrae, and connect to the lower spine which comprises the fivelumbar vertebrae. The base of the spine is the sacral bones (includingthe coccyx). The vertebrae which make up the cervical portion of thespine are generally smaller than those of the thoracic and lumbar spine.

Genetic or developmental irregularities, trauma, chronic stress, tumors,and disease are a few of the causes which can result in spinalpathologies for which permanent immobilization of multiple vertebrae maybe necessary. A variety of systems have been disclosed in the art whichachieve this immobilization by implanting artificial assemblies in or onthe spinal column. These assemblies may be classified as anterior,posterior, or lateral implants. As the classification suggests,posterior implants are attached to the back of the spinal column,generally hooking under the lamina and entering into the central canal,attaching to the transverse process, or coupling through the pediclebone. Lateral and anterior assemblies are coupled to the vertebralbodies.

The region of the back which needs to be immobilized, as well as theindividual variations in anatomy, determines the appropriate surgicalprotocol and implantation assembly. The use of posterior plates forstabilization and immobilization of the cervical spine is known. Aposterior plate is a narrow elongated plate having a series of spacedholes through which screws may be inserted to fix the plate to thevertebrae. A pair of posterior plates is placed across the lateralposterior surfaces of a set of sequential cervical bones and is securedto the bone by using one screw per vertebra, thereby preventing thebones from moving relative to one another in either the vertical orhorizontal planes.

Because the spine is routinely subject to high compression and torsionalloads which cycle during movement, one of the primary concerns ofphysicians performing spinal implantation surgeries, as well as of thepatients in whom the implants are placed, is the risk of screw pull-out.Screw pull-out occurs when the cylindrical portion of the bone whichsurrounds the inserted screw fails. A bone screw which is implantedperpendicular to the plate is particularly weak because the region ofthe bone which must fail for pull-out to occur is only as large as theouter diameter of the screw threads. It has been found that for pull-outto occur for screws which are inserted into the bone at an angle withrespect to the plate, the amount of bone which must fail increasessubstantially as compared with screws which are implantedperpendicularly with respect to the plate.

An additional concern with screws being implanted in the posterior sideof the cervical spine is that there are sensitive and importantstructures adjacent to the boney structures, such as the lateral massesand the laminae, which, because of their proximity to the implant, maybe damaged by insertion or dislocation of screws. In the cervical spine,the vertebral arteries are disposed medially beneath the lateral massesor lamina and comprise critical structures which cannot be compromised.In addition, the facet joints which provide natural coupling ofsequential bones together must also be avoided it possible. Avoidance ofthese bodies has been a critical and ongoing concern with respect toposterior screw insertion. Posterior plates of the prior art haveprovided little in the way of reasonable or practical solutions forensuring proper screw insertion.

Posterior screw plate assemblies necessarily include a plurality ofscrews which are inserted through a single plate. However, if a singlescrew loosens with respect to the surrounding bone into which it hasbeen inserted, loss of fixation occurs and possible neurologicalrepercussions may result.

One way to avoid the drawbacks of current plate systems has been to usefixation systems that employ polyaxial screws, rods, and hooks. However,while polyaxial screws provide a surgeon with the ability to locate thescrews in optimum locations, the ability to do so requires a high degreeof skill and experience. Further, to ensure proper placement ofpolyaxial screws, surgeons typically utilize fluoroscopy for an extendedperiod of time which can expose patients to unwanted radiation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a diagrammatic top view of a cervical vertebra.

FIG. 1B is a diagrammatic side view of two sequentially aligned cervicalvertebrae.

FIG. 2 is a diagrammatic posterior view of the cervical portion of thespine illustrating the lateral masses and lamina of the cervicalvertebrae.

FIG. 3 is a perspective view of a posterior vertebral plating systemconstructed in accordance with the inventive concepts disclosed herein.

FIG. 4A is a top plan view of a bone plate of the plating system of FIG.3.

FIG. 4B is a bottom plan view of the bone plate of FIG. 3.

FIG. 5A is an enlarged, perspective view of a portion of the bone plateof FIG. 3.

FIG. 5B is cross-sectional view taken along line 5B-5B of FIG. 5A.

FIG. 6 is a side elevational view of the bone plate of FIG. 3 shown in acurved condition.

FIG. 7A is a posterior, perspective view of a pair of the bone plates ofFIG. 3 shown connected to the posterior side of a plurality of vertebra.

FIG. 7B is a lateral, elevational view of one of the bone plates shownconnected to the posterior side of the plurality of vertebra.

FIG. 8 is a top plan view of another embodiment of a bone plateconstructed in accordance with the inventive concepts disclosed herein.

FIG. 9 is a partially cutaway, perspective view of the bone plate ofFIG. 8.

FIG. 10 is a cross-sectional view taken along line 10-10 of FIG. 9.

FIG. 11A is a partially cutaway, top plan view of the bone plate of FIG.8.

FIG. 11B is a partially cutaway, top plan view of another embodiment ofa bone plate constructed in accordance with the inventive conceptsdisclosed herein.

FIG. 12 is a posterior, perspective view of the bone plate of FIG. 8shown connected to a plurality of vertebrae along one posterior side ofthe vertebrae.

FIG. 13A is a top plan view of another embodiment of a bone plateconstructed in accordance with the inventive concepts disclosed herein.

FIG. 13B is a top plan view of another embodiment of a bone plateconstructed in accordance with the inventive concepts disclosed herein.

FIG. 14 is a top plan view illustrated the bone plate of FIG. 12 nestedwith the bone of FIG. 13.

FIG. 15 is a top plan view of another embodiment of a bone plateconstructed in accordance with the inventive concepts disclosed herein.

FIG. 16 is a top plan view of another embodiment of a bone plateconstructed in accordance with the inventive concepts disclosed herein.

FIG. 17 is a top plan view of another embodiment of a bone plateconstructed in accordance with the inventive concepts disclosed herein.

FIG. 18 is a side elevational view of another embodiment of a bone plateconstructed in accordance with the inventive concepts disclosed herein.

FIG. 19 is a top perspective view of another embodiment of a bone plateconstructed in accordance with the inventive concepts disclosed herein.

FIG. 20 is a top perspective view of another embodiment of a bone plateconstructed in accordance with the inventive concepts disclosed herein.

FIG. 21 is a top perspective view of another embodiment of a bone plateconstructed in accordance with the inventive concepts disclosed herein.

FIG. 22A is a top plan view of another embodiment of a bone plateconstructed in accordance with the inventive concepts disclosed hereinhaving a rod portion incorporated therein.

FIG. 22B is an end elevational view of the bone plate of FIG. 22A.

FIG. 23A is a perspective view of a pair of the bone plates of FIG. 22Ashown connected to the posterior side of a plurality of vertebra andinterconnected with a cross-linking connector and showing a laminaconnector connected to one of the bone plates.

FIG. 23B is a perspective view of another embodiment pair of bone platesshown connected to the posterior side of a plurality of vertebra andinterconnected with another embodiment of a cross-linking connector andshowing another embodiment of a lamina connector connected to one of thebone plates.

FIG. 23C is an end elevational view of a portion of the bone plate ofFIG. 8 shown with a linking connector connected thereto.

FIG. 23D is a perspective view of the linking connector of FIG. 23Cshown connected to the bone plate of FIG. 8.

FIG. 24 is a perspective view of another embodiment of a bone plateconstructed in accordance with the inventive concepts disclosed hereinhaving a rod portion incorporated therein.

FIG. 25A is a perspective of another embodiment of a bone plateconstructed in accordance with the inventive concepts disclosed herein.

FIG. 25B is an end elevational view of the bone plate of FIG. 25A.

FIG. 25C is an end elevational view of the bone plate of FIG. 8 shownwith a bone graft ridge connected thereto.

FIG. 26 is an end elevational view of another embodiment of a bone plateconstructed in accordance with the inventive concepts disclosed herein.

FIG. 27 is a lower perspective view of another embodiment of a boneplate constructed in accordance with the inventive concepts disclosedherein having bosses formed thereon for engagement with an adjacent boneplate.

FIG. 28 is a perspective view of another embodiment of a bone plateconstructed in accordance with the inventive concepts disclosed herein.

FIG. 29A is a perspective view of another embodiment of a bone plateconstructed in accordance with the inventive concepts disclosed herein.

FIG. 29B is a perspective view of a portion of another version of thebone plate of FIG. 29A.

FIG. 30 is a perspective view of a portion of another embodiment of abone plate constructed in accordance with the inventive conceptsdisclosed herein.

FIG. 31A is a perspective view of another embodiment of a pair of boneplates constructed in accordance with the inventive concepts disclosedherein.

FIG. 31B is a perspective view illustrating the bone plates of FIG. 29Aconnected to the C1 and C2 vertebrae.

FIG. 32A is a perspective view of another embodiment of a pair of boneplates constructed in accordance with the inventive concepts disclosedherein.

FIG. 32B is a perspective view illustrating the bone plates of FIG. 30Aconnected to the C1 and C2 vertebrae.

FIG. 33A is a perspective view of another embodiment of a pair of boneplates constructed in accordance with the inventive concepts disclosedherein.

FIG. 33B is a perspective view illustrating the bone plates of FIG. 31Aconnected to the C1 and C2 vertebrae.

FIG. 34A is an exploded, perspective view of another embodiment of abone plate constructed in accordance the inventive concepts disclosedherein.

FIG. 34B is a perspective view of the bone plate of FIG. 34A.

FIG. 34C is a sectional view of the bone plate of FIG. 34B.

FIG. 35A is an elevational view of an embodiment of a post.

FIG. 35B is an elevational view of another embodiment of a post.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Before explaining at least one embodiment of the presently disclosedinventive concepts in detail, it is to be understood that the presentlydisclosed inventive concepts are not limited in their application to thedetails of construction, experiments, exemplary data, and/or thearrangement of the components as set forth in the following descriptionor illustrated in the drawings. The presently disclosed inventiveconcepts are capable of other embodiments or of being practiced orcarried out in various ways. Also, it is to be understood that thephraseology and terminology employed herein is for purpose ofdescription and convenience and should not be regarded as limiting.

Referring now to the drawings, and more particularly to FIGS. 1A, 1B,and 2, a typical cervical vertebra 10 is shown in a superior view inFIG. 1A; two adjacent cervical vertebrae 10 are shown in a lateral viewin FIG. 1B; and the cervical vertebrae are shown from a posterior viewin FIG. 2. The spinal cord (not shown) is housed within a central canal12 that runs the length of the spinal column and is protected along theposterior side of the spinal column by a bony arch, or roof, made up ofa pair of lamina 14 and a rearward (dorsally) and downwardly extendingportion called the spinous process 16 located between the two laminae14. Two laterally extending bulk structures, one on either side of eachlamina 14, define the two lateral masses 18. The portions of thevertebrae 10 which define the anterior portion of the spine comprisecylindrically shaped bone portions which are stacked one on top of theother. These portions of the vertebrae 10 are referred to as vertebralbodies 20 and are separated from each other by intervertebral discs 22which provide a cushioning effect between the vertebrae 10. The lateralmasses 18 comprise a pair of bone bridges which couple the anteriorvertebral body 20 to the laminae 14 of the same vertebra 10

Referring now to FIGS. 3-7B, a posterior vertebral plating system 30constructed in accordance with the inventive concepts disclosed hereinis shown. Although intended for use primarily in the cervical portion ofthe spine, it should be understood that the posterior vertebral platingsystem 10 may be used on any boney structure of the spine, includinglumbar, thoracic, and sacral, and the plating system 10 can be used inany direction, e.g., posterior, anterior, or lateral.

The posterior vertebral plating system 30 includes a bone plate 32 and aplurality of attachment members 34. As used herein, the term “attachmentmember” is intended to refer to any member that may be used to attach abone plate to a vertebral bone surface, including, but not limited to,screws, clamps, wire, compression screws, locking screws, tacks, pins,nails, studs, rivets, fasteners, or other such devices known to personshaving ordinary skill in the art.

The bone plate 32 is intended to stabilize multiple vertebrae. To thisend, the bone plate 32 has a length dimensioned to extend along theposterior side of at least two vertebrae. It will be appreciated thatthe length of the bone plate 32 may be varied depending on the number ofvertebrae to be stabilized. Because the bone plate 32 is intended to befixed to boney structures of the posterior side of vertebrae (e.g.,lateral mass, lamina), the plate 32 has a width and shape that allowsthe bone plate 32 to be positioned over the boney structures of theposterior side of adjacent vertebrae. In one embodiment, the bone plate32 may have an overall width in a range from about 8 mm to about 14 mm,but more desirably, less than about 12 mm. The width of the bone plate32 may be varied or curved or contoured along one side such that thebone plate 32 is configured to have a plurality of nodes 36 which definerecesses 38 between each of the nodes 36 to reduce the outer contour andsize of the bone plate 32. To this end, the bone plate 32 may have atleast one minor width 40 at a most narrow portion and at least one majorwidth 42 at a widest portion. In one embodiment, the minor width 40 maybe approximately 5 mm and the major width 42 in a range of approximately9 mm to 12 mm. The reduced width portion between each of the nodes 36provides an area of reduced material for bending of the bone plate 32 asmay be required by the spinal anatomy, as well as provides for bettervisualization of the boney surface below the bone plate 32. The boneplate 32 has a thickness 44, which may be in a range including, but notlimited to, about 1 mm to about 4 mm, for example.

The bone plate 32 has an upper surface 46 and a lower surface 48. Thebone plate 32 can include a rounded upper edge 50 to reduce irritationof surrounding tissue. The rounded upper edge 50 reduces the amount oftrauma or irritation that would be experienced by the surrounding softtissue. The lower surface 48 of the bone plate 32 may be configured toconform to the contour of the vertebral bodies at each of theinstrumented levels of the spine. In some embodiments, the lower surface48 can be provided with a textured surface 52 (FIG. 4B) which mayinclude a variety of geometric shapes and/or protrusions, such asspikes, or other features, such as ridges, posts, pockets, or be treatedsuch as bead blasted or acid etched to enhance its grip on the vertebralbody. The bone plate 32 may also have a longitudinal and/or transversecurvature to match the corresponding attachment surface (e.g., the curveof the spine).

The bone plate 32 has a plurality of holes 56 which extend through thebone plate 32 from the upper surface 46 through the lower surface 48.The holes 56 are dimensioned and arranged relative to one another sothat more than one of the holes 56 is positionable or alignable over theposterior boney structures, such as the lateral mass or lamina, of eachvertebra to define a plurality of fixation points per vertebra. Theholes 56 may be arranged in a variety of ways to provide multiple pointsof fixation while maintaining the structural strength and rigidity ofthe bone plate 32. FIGS. 4A and 4B illustrate one exemplary embodimentof a hole pattern where the holes 56 are arranged in a plurality ofgroups of holes 58 a-58 e (corresponding with one of the nodes 36) insuch a way that at least two to three of the holes 56 is positionableover a single vertebra to define a plurality of fixation points pervertebra. The holes 56 are shown to be arranged in groups of three holes58 a-58 e with the holes 56 in each group being arranged in a triangularpattern. In one version, the holes 56 may be arranged in at least twolongitudinal rows of holes 56 along the length of the bone plate 32 withthe holes 56 of one longitudinal row of holes being staggered and nestedrelative to the holes 56 of the other longitudinal row of holes 56.

Each group of three holes 58 a-58 e of holes 56 may be arranged whereeach laterally adjacent pair of holes is spaced substantially an equaldistance and each laterally adjacent pair of holes angled relative toone another in a range from about 30 degrees to about 50 degreesrelative to the longitudinal axis of the bone plate 32 so as to resultin an overlap of laterally adjacent holes 56 along a longitudinal axisof not more than about 20% (e.g., approximately 10%) of the area of theholes 56 so as to permit longitudinally adjacent holes 56 to remainspaced to align with the lateral mass of the vertebra. Accordingly, itshould be apparent that each pair of longitudinally adjacent holes isspaced a greater distance than the laterally adjacent holes. By way ofexample, the holes 56 may have a diameter to accommodate a screw havingan outer diameter in a range from about 1.5 mm to about 3.0 mm (e.g.,approximately 2.7 mm), each laterally adjacent pair of holes may bespaced a lateral distance (center to center) in a range from about 2.0mm to about 4.0 mm (e.g., approximately 2.9 mm) and a longitudinaldistance (center to center) in a range of from about 3.0 mm to about 5.0mm (e.g., approximately 3.5 mm), and each longitudinally adjacent pairof holes may be spaced a longitudinal distance (center to center) in arange from about 6.0 mm to about 8.0 mm (e.g., approximately 7.0 mm)resulting in a bone plate with a width less than 10 mm and a three holepattern that provides a ratio of hole area/plate area (footprint) in arange of from about 40% to about 60% (e.g., approximately 47%).

The bone plate 32 depicted in FIGS. 6A and 6B includes five nodes andfive groupings of holes, and the bone plate 32 has a length so that thebone plate 32 can be engaged to five cervical vertebrae of the spine.However, the bone plate 32 can be configured to fix any number ofvertebrae depending upon the length of the bone plate 32 and the numberand arrangement of attachment members.

In one exemplary version of the bone plate 32, each group of holes 58a-58 e is spaced apart from the adjacent group of holes a distance whichis generally greater than the distance between laterally adjacent holes56. Such an arrangement facilitates bending or curving the bone plate 32to a desired configuration, such as illustrated in FIG. 6, by way ofexample. To aid in bending the bone plate 32, the bone plate may beprovided with transverse grooves 60 in one of the upper surface 46 andthe lower surface 48, or both the upper surface 46 and the lower surface48.

The holes 56 may be formed entirely perpendicular to the plane of thebone plate 32, or may be offset in the general direction which screwangulation is desired to aid in minimizing the risk of comprisingvascular and neural structures. For example, the holes 56 may belaterally outwardly angled, e.g., at an angle of approximately 10 to 30degrees of lateral outward angulation.

Referring to FIGS. 4A, 5A and 5B, each hole 56 is shown to be threadedto receive one of the attachment members 34. Those skilled in the artwill understand that any thread configuration may be used, or the holes56 may even be smooth or non-threaded. In FIGS. 4A, 5A and 5B, each hole56 is illustrated as being threaded to receive an attachment member 34in the form of a variable angle locking screw 34 a. The holes 56 have aplurality of columns of threads 62 spaced apart to define a plurality ofnon-threaded recesses 64. In the embodiment illustrated herein, each ofthe holes 56 has four columns of threads 62. The columns of threads 62are arranged around the inner surface of each of the holes 56 forengaging threads on a head of locking and variable-angle locking bonescrews. Conventional locking screws engage the bone plate 32 coaxiallywith the central axis of the hole of the bone plate 32. Variable-anglelocking screws can engage the bone plate 32 at a selected angle within arange of selectable angles relative to the central axis of hole of thebone plate 32. An example of a variable angle locking screw 34 a isillustrated in FIG. 3. The variable-angle locking screw 34 a has a head34 b which is at least partially spherical and a thread 34 c which has aprofile that follows the arc-shaped radius of curvature of the sphericalportion of the head 34 b. Variable angle locking screws are well knownin the art such as disclosed in U.S. 2008/0140130 filed by Chan et al.,for example, which is hereby expressly incorporated herein by reference.

During implantation, the variable angle capability of the variable anglelocking screw 34 a allows a surgeon to place the variable angle lockingscrew 34 a within the vertebra at any angle within defined angulationlimits. Thus, the variable angle locking screw 34 a provides greaterflexibility than does a fixed angle screw.

As best shown in FIGS. 5A and 5B, the holes 56 may be provided with aflange 66 extending between adjacent columns of threads 62 hole near thelower surface 48 of the bone plate 32 in such a way that the flange 66functions to obstruct the attachment member 34, such as the variableangle screw 34 a, from being driven too deeply into the vertebra andthereby limit the risk of injury to patients. In one embodiment, theflanges 66 are formed coextensively with respect to the lower mostthread of the columns of threads 62 so as to engage with the threads 34c of the head 43 b of the variable angle locking screw 34 a upon thehead 34 b of the variable angle locking screw 34 a being fully driveninto the hole 56 and thereby provide an obstruction to the variableangle locking screw 34 a. It should be appreciated that the attachmentmember 34 may alternatively, or in addition to, have a flange element orstop member that contacts a portion of the bone plate 32 to limit thedepth or distance which the attachment element 34 may be inserted intothe bone.

Due to the relatively narrow width of the bone plate 32 and theinclusion of multiple groups of holes, the holes 56 are necessarilypositioned relatively close to one another. As such, the strength of thebone plate 32 can be compromised along the narrowest portions of thebone plate 32. As described above, one of those narrow portions isgenerally located between laterally adjacent holes 56. To increase thestrength in these areas, at least one of the columns of threads 62 a ofone of the holes 56 of a pair of laterally adjacent holes intersects aline 68 (FIG. 4A) extending between the axes of the holes 56 of the pairof laterally adjacent holes 56. Moreover, in certain arrangements, suchas shown in FIG. 4A, one of the columns of threads 62 a of each of theholes 56 of a pair of laterally adjacent holes intersects and is alignedwith the line 68 extending between the axes of the holes 56 of the pairof laterally adjacent holes 56, such that the columns of threads 62function to provide a thicker area between two laterally adjacent holesthan would exist if the non-threaded recesses 64 were aligned. Thethicker area provides the advantage of increased strength of the boneplate 32.

Referring now to FIGS. 7A and 7B, the posterior spinal fixation system30 is illustrated as being connected to the posterior side of aplurality of vertebrae 10 with the bone plates 32 extending along theposterior side of five vertebrae 10 adjacent the lateral masses 18 ofeach of the vertebra 10 and the holes 56 being spaced in such a way thata plurality of holes 56 is positioned over the lateral mass 18 of eachof the vertebra 10 to define a plurality of fixation points to each ofvertebra 10. The attachment members 34 are inserted through selectedholes 56 and into the lateral mass 18 of a corresponding vertebra 10 tofix the bone plate 32 to the vertebrae 10. It will be appreciated thatthe user can elect not to insert an attachment member 34 into selectedholes.

Referring now to FIGS. 8-11, another embodiment of a bone plate 32 a isillustrated. The bone plate 32 a is similar structure and function tothe bone plate 32 described above. The bone plate 32 a is intended tostabilize multiple vertebrae. To this end, the bone plate 32 a has alength dimensioned to extend along the posterior side of at least twovertebrae. It will be appreciated that the length of the bone plate 32 amay be varied depending on the number of vertebrae to be stabilized.Because the bone plate 32 a is intended to be fixed to boney structuresof the posterior side of vertebrae (e.g., lateral mass, lamina), thebone plate 32 a has a width and shape that allows the bone plate 32 a tobe positioned over the boney structures of the posterior side ofadjacent vertebrae. In one embodiment, the bone plate 32 a may have awidth less than about 15 mm, but more desirably, less than about 12 mm.

The bone plate 32 a has an upper surface 70 and a lower surface 72. Thebone plate 32 can include a rounded upper edge 74 to reduce irritationof surrounding tissue. The rounded upper edge 74 reduces the amount oftrauma or irritation that would be experienced by the surrounding softtissue. The lower surface 72 of the bone plate 32 a may be configured toconform to the contour of the vertebral bodies at each of theinstrumented levels of the spine. In some embodiments, the lower surface48 can be provided with a textured surface such that described above inreference to FIG. 4B which may include a variety of geometric shapesand/or protrusions, such as spikes, or other features, such as ridges,posts, pockets, or be treated such as bead blasted or acid etched toenhance its grip on the vertebral body. The bone plate 32 a may alsohave a longitudinal and/or transverse curvature to match thecorresponding attachment surface (e.g., the curve of the spine).

The bone plate 32 a has a plurality of holes 76 which extend through thebone plate 32 a from the upper surface 70 through the lower surface 72.The holes 76 may be entirely perpendicular to the plane of the boneplate 32 a, or may be offset in the general direction which screwangulation is desired. For example, the holes 76 may be laterallyoutwardly angled, e.g., at an angle of approximately 10 to 30 degrees oflateral outward angulation.

The holes 76 are dimensioned and arranged relative to one another sothat more than one of the holes 76 is positionable or alignable over theboney structure, such as a lateral mass or lamina, of each vertebra todefine a plurality of fixation points per vertebra. The holes 76 may bearranged in a variety of ways to provide multiple points of fixationwhile maintaining the structural strength and rigidity of the bone plate32 a. FIGS. 8, 9, and 11A illustrate one embodiment of a hole patternwhere the holes 76 are arranged in two longitudinal rows of holes 76along the length of the bone plate 32 a with the holes 76 of onelongitudinal row of holes being staggered relative to the holes 76 ofthe other longitudinal row of holes 76. Each of the holes 76 may bearranged where each laterally adjacent pair of holes 76 are spacedsubstantially a first distance, and each pair of longitudinally adjacentholes are spaced substantially a second distance where the seconddistance is greater than the first distance and each laterally adjacentpair of holes are angled relative to one another in a range from about45 degrees to about 65 degrees (e.g., approximately 57 degrees) relativeto the longitudinal axis of the bone plate 32 a.

To increase the number of holes per unit length, the holes 76, whileshown as being staggered, are not overlapped with one another along alongitudinal axis. However, an innermost point of each of the holes 76may be aligned with a longitudinal axis 77 to minimize the width of theplate. By way of example, the holes 56 may have a diameter toaccommodate a screw having an outer diameter in a range from about 1.5mm to about 3.0 mm. (e.g., approximately 2.7), each laterally adjacentpair of holes may be spaced a lateral distance in a range from about 3.0mm to about 5.0 mm (e.g., approximately 4.2 mm) and a longitudinaldistance in a range of from about 2.0 mm to about 5.0 mm (e.g.,approximately 2.8 mm), and each longitudinally adjacent pair of holesmay be spaced a longitudinal distance in a range from about 4.0 mm toabout 7.0 mm (e.g., approximately 5.5 mm) resulting in a bone plate witha width less than 12 mm and a four hole pattern providing a ratio ofhole area/plate area (footprint) in a range of from about 40% to about60% (e.g., approximately 49%).

The bone plate 32 a can be configured to fix several vertebrae dependingupon the size/length of the bone plate 32 a and the number andarrangement of attachment members. For example, the bone plate 32 adepicted in FIG. 8 includes nine holes 76 in each longitudinal row, andthe bone plate 32 a has a length so that the bone plate 32 a can beattached to five cervical vertebrae of the spine.

Like the holes 56 described above, the hole 76 are shown to be threadedto receive one of the attachment members 34. Those skilled in the artwill understand that any thread configuration may be used, or the holes76 may even be non-threaded or smooth. As best shown in FIGS. 9 and 10,each of the holes 56 is illustrated as being threaded to receive anattachment member 34 in the form of a variable angle locking screw 34 a(FIG. 3). The holes 76 have a plurality of columns of threads 82 spacedapart to define a plurality of non-threaded recesses 84. In theembodiment illustrated herein, each of the holes 76 has four columns ofthreads 82. The columns of threads 82 are arranged around the innersurface of each of the holes 76 for engaging threads on a head oflocking and variable-angle locking bone screws. Conventional lockingscrews engage the bone plate 32 a coaxially with the central axis of thehole of the bone plate 32 a. Variable-angle locking screws can engagethe bone plate 32 a at a selected angle within a range of selectableangles relative to the central axis of hole of the bone plate 32 a.

As best shown in FIGS. 9 and 10, the holes 56 may be provided with aflange 86 extending between adjacent columns of threads 82 hole near thelower surface 72 of the bone plate 32 a in such a way that the flange 86functions to obstruct the attachment member 34, such as the variableangle screw 34 a, from being driven too deeply into the vertebra andthereby limit the risk of injury to patients. In one embodiment, theflanges 86 are formed coextensively with respect to the lower most toothof the columns of threads 82 so as to engage with the threads 34 c ofthe head 43 b of the variable angle locking screw 34 a upon the head 34b of the variable angle locking screw 34 a being fully driven into thehole 76 and thereby provide an obstruction to the variable angle lockingscrew 34 a.

Due to the relatively narrow width of the bone plate 32 a and theinclusion of multiple holes, the holes 76 are necessarily positionedrelatively close to one another. As such, the strength of the bone plate32 a can be compromised along the narrowest portions of the bone plate32 a. As described above, one of those narrow portions is generallylocated between laterally adjacent holes 76. To increase the strength inthese areas, at least one of the columns of threads 82 a of one of theholes 76 of a pair of laterally adjacent holes intersects a line 88(FIG. 11A) extending between the axes of the holes 76 of the pair oflaterally adjacent holes 76 such that the columns of threads 62 functionto provide a thicker area between two laterally adjacent holes thanwould exist if the non-threaded recesses 84 were aligned. The thickerarea provides the advantage of increased strength of the bone plate 32a.

FIG. 11B illustrates a modified version of the bone plate 32 aillustrating the holes 76 arranged in such a manner that the spacingbetween laterally adjacent holes is minimized whereby the opposing pairsof columns of threads 82 generally provide the structure between eachlaterally adjacent pair of holes 76.

FIG. 12 shows the bone plate 32 a connected to the posterior side of aplurality of vertebrae 10 with the bone plates 32 a extending along theposterior side of four vertebrae 10 adjacent the lateral masses 18 ofeach of the vertebrae 10 and the holes 76 being spaced in such a waythat a plurality of holes 76 is positioned over the lateral mass 18 ofeach of the vertebrae 10 to define a plurality of fixation points toeach of vertebrae 10. The attachment members 34 are inserted throughselected holes 76 and into the lateral mass 18 of a correspondingvertebra 10 to fix the bone plate 32 a to the vertebrae 10.

FIG. 13A shows another embodiment of a bone plate 32 b constructed inaccordance with the inventive concepts disclosed herein. The bone plate32 b is similar to the bone plate 32 a, except that the bone plate 32 bhas a plurality of holes 90 arranged in two longitudinal rows with theholes 90 of each row positioned directly laterally of a hole 90 in theother row. The holes 90 are sized and spaced apart from one another suchthat two or more of the holes 90 are positionable or alignable over thelateral mass of a single vertebra to define a plurality of fixationpoints per vertebra. Further, the bone plate 32 b is illustrated ashaving a perimeter edge 92 extending between the upper surface and thelower surface which is configured to substantially conform to thecontour of the holes 90 of the of the bone plate 32 b to define aplurality of nodules and recesses.

FIG. 13B shows a version of a bone plate 32 c constructed in accordancewith the inventive concepts disclosed herein. The bone plate 32 c issimilar to the bone plate 32 b, except that the bone plate 32 b has asingle longitudinal row of holes 94. The holes 94 are sized and spacedapart from one another such that at least two of the holes 94 arepositionable or alignable over the lateral mass or lamina of a singlevertebra to define a plurality of fixation points per vertebra. Further,the bone plate 32 c has a perimeter edge 96 extending between the uppersurface and the lower surface which is configured to substantiallyconform to the contour of the holes 94 of the of the bone plate 32 c todefine a plurality of nodules and recesses.

FIG. 14 illustrates the bone plate 32 b nested or engaged with the boneplate 32 c along one side of corresponding edges of the bone plates 32 band 32 c. In such an embodiment of paired bone plates 32 b and 32 c, thebone plate 32 b can be attached to the lateral masses, while the boneplate 32 c can be attached to the corresponding lamina.

FIG. 15 illustrates another embodiment of a bone plate 32 d constructedin accordance with the inventive concepts disclosed herein. The boneplate 32 d is similar to the bone plate 32 b. That is, the bone plate 32d has a plurality of holes 98 arranged in two longitudinal rows with theholes 98 of each row positioned directly laterally of a hole 98 in theother row. The holes 98 are sized and spaced apart from one another suchthat at least two of the holes 98 are positionable or alignable over thelateral mass or lamina of a single vertebra to define a plurality offixation points per vertebra. However, the bone plate 32 d isillustrated as having a perimeter edge 200 extending between the uppersurface and the lower surface which is substantially straight ornon-contoured.

FIG. 16 illustrates another embodiment of a bone plate 32 e constructedin accordance with the inventive concepts disclosed herein. The boneplate 32 e is similar to the bone plate 32 illustrated in FIG. 3, exceptthat the bone plate 32 e is shown to have vertically-oriented grooves202 extending along either or both outer edges from the upper surface tothe lower surface to facilitate bending of the bone plate 32 e along acoronal plane.

FIG. 17 illustrates another embodiment of a bone plate 32 f constructedin accordance with the inventive concepts disclosed herein. The boneplate 32 f is similar to the bone plate 32 illustrated in FIG. 3, exceptthat the bone plate 32 f has a plurality of groups of holes 204 a-204 fand the distance which the groups of holes 204 a-204 f are spaced fromone another increases sequentially from one of the bone plate 32 f tothe other end. By way of example, as measured from node to node, thegroups of holes 204 a-204 f may be spaced at intervals of 13 mm, 14 mm,15 mm, 16 mm, and 17 mm.

FIG. 18 illustrates another embodiment of a bone plate 32 g constructedin accordance with the inventive concepts disclosed herein. The boneplate 32 g is similar to the bone plate 32 illustrated in FIG. 3, exceptthat the bone plate 32 g is tapered along a longitudinal axis such thatone end of the bone plate 32 g has a minor thickness 206 which is lessthick than the other end which has a major thickness 208. By way ofexample, the minor thickness 206 may be 1.85 mm and the major thickness208 may be 2.65 mm.

FIGS. 19-21 illustrate bone plates 32 h, 32 i, and 32 j constructed inaccordance with the inventive concepts disclosed herein. The bone plate32 h, 32 i, and 32 j are configured to be bent along a longitudinalaxis. The bone plate 32 h has longitudinal groove 210 to facilitatebending of the bone 32 h so as to define a lateral mass plate portion212 and a lamina plate portion 214. The lateral mass plate portion 212and the lamina plate portion 214 each have a plurality of holes 216arranged in two longitudinal rows such the lateral mass plate portion212 is attachable to the lateral masses of the corresponding vertebraeand the lamina plate portion 214 is attachable to the lamina of thecorresponding vertebra with suitable attachment members.

The bone plate 32 i is similar to the bone plate 32 h except the boneplate 32 i has a lamina plate portion 218 which has a plurality of tabs219 which are individually bendable relative to the other tabs 219. Eachtab 219 is shown as having two holes 220 for receiving attachmentmembers.

The bone plate 32 j is similar to the bone plate 32 i, except the boneplate 32 j has a lateral mass plate portion 221 shown to have aplurality of holes 222 arranged in a single longitudinal row forreceiving attachment members.

Referring now to FIGS. 22A, 22B, and 23A, another embodiment of a boneplate 32 k constructed in accordance with the inventive conceptsdisclosed herein is illustrated. The bone plate 32 k is shown as beingsimilar to the bone plate 32 a described above except that the boneplate 32 k has a longitudinal edge 224 and a rod portion 226 formedalong the inner longitudinal edge 224. Besides providing added strengthand stiffness to the bone plate 32 k, the rod portion 226 may serve asan attachment point for auxiliary implements. For example, asillustrated in FIG. 23A, the rod portion 226 may be used as a point ofattachment for a cross-linking connector 228. The cross linkingconnector 228 may include a rod portion 230 and a rod engaging portion232 formed on each end of the rod portion 230. The rod engaging portions232 may be in the form of a C-shaped clamp mateable with the rod portion230 of the bone plate 32 k and a securement member, such as a set screw233. The rod portion 230 has a length (or may configured for selectivetranslation) so that the rod portion 230 extends from one side of avertebra to an opposing side of the vertebra when one of the rodengaging portions 232 is engaged with the rod portion 226 of the boneplate 32 k and the bone plate 32 k is connected to the lateral masses ofa plurality of vertebrae and the other rod engaging portions 232 isengaged with the rod portion 226 of another bone plate 32 k and theother bone plate 32 k is connected to the opposing lateral masses of thevertebrae.

The rod portion 226 may also be used as a point of attachment for alamina connector 234 for fixing an arch during a laminoplasty procedure.As shown in FIG. 23A, the lamina connector 234 may have a plate portion236 and a rod engaging portion 238. The rod engaging portion 238 may bein the form of a C-shaped clamp mateable with the rod portion 230 of thebone plate 32 k and a securement member, such as a set screw 233. Theplate portion 236 has a hole for receiving an attachment member, such asa screw 242. The plate portion 236 may be configured to for translationin a manner well known in the art. The plate portion 236 is positionableover a lamina of a vertebra and when the rod engaging portion 238 isengaged with the rod portion 236 of the bone plate 32 k and the boneplate 32 k is connected to the lateral masses of a plurality ofvertebrae.

FIG. 23B illustrates alternative embodiments of a cross linkingconnector 228 a and a lamina connector 234 a which are similar to thecross linking connector 228 and the lamina connector 234, respectively,except that the cross linking connector 228 a and the lamina connector234 a are configured to be attached to a bone plate, such as the boneplate 32 a, employing the holes 76 of the bone plate 32 a used forfixing the bone plate 32 a to vertebra or to alternative holes (notshown) which may be provided in the bone plate for attaching auxiliaryimplements thereto.

The cross linking connector 228 a includes a rod portion 241 and a plateportion 242 formed on each end of the rod portion 241. The plateportions 242 are shown as being provided with a plurality of holes whichare alignable with a plurality of holes 76 of the bone plates 32 a suchthat the plate portions 244 may be attached to the upper surface of thebone plates 32 a with a plurality of attachment members, such as screws246.

Similarly, the lamina connector 234 a may include a first plate portion248 and a second plate portion 250 where the second plate portion 250 issimilar in construction and function to the plate portion 242 describedin reference to the cross linking connector 228 a.

FIGS. 23C and 23D illustrate an embodiment of a linking connector 228 bwhich is similar to the cross linking connector 228 a, except that thelinking connector 228 b includes plate portion 241 a and a rod receivingmember 242 a. The plate portion 241 a is provided with a plurality ofholes which are alignable with a pair of holes 76 of the bone plate 32 asuch that the plate portion 241 a may be attached to the upper surfaceof the bone plate 32 a with a plurality of attachment members, such asscrews 246.

When the plate portion 241 a is connected to the bone plate 32 a, therod receiving member 242 a is oriented to receive a rod 244 which islongitudinally extended along the spine to be positioned so as to beconnectable to other implements implanted in other vertebrae to whichthe bone plate 32 a is not directly attached, such as one or morepolyaxial screws. The rod 244 may be secured in the rod receiving member241 a with an attachment member, such as a set screw 249.

FIG. 24 illustrates another embodiment of a bone plate 32 j constructedin accordance with the inventive concepts disclosed herein. The boneplate 32 j is similar to the bone plate 32 k described above, except thebone plate 32 j has a rod portion 226 a formed along a longitudinal edgeof the bone plate 32 j such that the rod portion 226 a may serve as anattachment point for auxiliary implements. The rod portion 226 a furtherhas a rod extension portion 252 which extends a distance beyond at leastone end of the bone plate 32 k so as to be connectable to otherimplements implanted in other vertebrae to which the bone plate 32 j isnot directly attached, such as one or more polyaxial screws. To thisend, the rod extension portion 252 may be configured to be positioned ina rod receiving head of polyaxial screw assembly in a manner similar tothe way a spinal rod (not shown) would be positioned in a rod receivinghead of a polyaxial screw assembly. It should be appreciated that thelength of the rod extension portion 252 may be varied during manufactureor customized prior to attachment to a patient.

Referring now to FIGS. 25A and 25B, another embodiment of a bone plate32 m constructed in accordance with the inventive concepts disclosedherein is illustrated. The bone plate 32 m is illustrated as beingsimilar in construction to the bone plate 32 a described above, exceptthe bone plate 32 m has an outer longitudinal edge 254 with a bone graftridge 256 extending upwardly and outwardly from the outer longitudinaledge 254 of the bone plate 32 m. The bone graft ridge 256 functions todefine a pocket or void 258 in cooperation with the surface of thevertebrae so that biologic material may be packed in the pocket 258 tofacilitate the formation of a graft between two vertebrae. Such biologicmaterial can include, but is not limited to, medicine, human tissue,animal tissue, synthetic tissue, human cells, animal cells, syntheticcells, and the like.

FIG. 25C illustrates another version of a bone graft ridge 256 a whichis formed by a separate piece which may be connected to a bone plate,such as the bone plate 32 a, in any suitable fashion, such as withscrews (now shown).

FIG. 26 illustrates another embodiment of a bone plate 32 n constructedin accordance with the inventive concepts disclosed herein. The boneplate 32 n is similar to the bone plates described above, except thebone plate 32 n has a pair of flanges 260 a and 260 b extendingdownwardly from the lower surface thereof along an inner longitudinaledge 262 and an outer longitudinal edge 264 so as to define a pocket 266in which biologic material may be packed to facilitate the formation ofa graft between two vertebrae.

FIG. 27 illustrates another embodiment of a bone plate 32 o that issimilar to the plates discussed above, except that the bone plate 32 ois provided with a plurality of protrusions 267 extending from a lowerside 268 of the bone plate 32 o near one end thereof. The protrusions267 are configured and arranged to align with and fit in a group ofholes of another bone plate in such a way that the two plates may beinterlocked with one another. The bone plate 32 o may be contoured sothat the bone plate 32 o may be positioned on another bone plate in anoverlapping relationship, while permitting the bone plate 32 o to beattached to vertebrae in the manner discussed above with attachmentmembers 34.

FIG. 28 illustrates yet another embodiment of a bone plate 32 qconstructed in accordance with the inventive concepts disclosed herein.The bone plate 32 q includes a first plate portion 270 and a secondplate portion 272. By way of example, the first plate portion 270 andthe second plate portion 272 are illustrated as being similar inconfiguration to the bone plate 32 a described above. The first plateportion 270 is longitudinally aligned with the second plate portion 272,and the first plate portion 270 is pivotally connected to the secondplate portion 272. In one embodiment, the first plate portion 270 may bepivotally connected to the second plate portion 272 via a locking hinge274 to allow the first plate portion 272 and the second plate portion274 to be fixed in a desired angular relationship relative to oneanother, whether about a single axis or multiple axes, particularly whenused for occipital-cervical fusion or deformity correction.

FIG. 29A is a bottom perspective view of another embodiment of a boneplate 32 r constructed in accordance with the inventive conceptsdisclosed herein is illustrated. The bone plate 32 r is illustrated asbeing similar in construction to the bone plate 32 a, except the boneplate 32 r is provided with a hook 276 extending substantially normal tothe longitudinal axis of the bone plate 32 r. The hook 276 is configuredto be received on the posterior arch of the C1 vertebra when the boneplate 32 r is connected to the adjacent vertebrae of the spine asdiscussed above. To this end, it should be appreciated that the hook 276may be formed at various angles relative to the longitudinal axis of thebone plate 32 r to be received at selected positions on the arch of theC1 vertebra. As shown in FIG. 29B, the bone plate 32 r may be furtherprovided with a retaining groove 278 formed on an outer surface of thehook 276 to retain a cable or wire (not shown) which may be extendedabout the hook 276 and the ring of the C1 vertebra to further hold thehook 276 in place on the ring.

FIG. 30 illustrates another version of a bone plate 32 s which issimilar to the bone plate 32 r except the bone plate 32 s includes aplatform 280 extending substantially normal to the longitudinal axis ofthe bone plate 32 s. The platform 280 is configured to be positioned onthe ring of the C1 vertebra when the bone plate 32 s is connected to theadjacent vertebrae of the spine as discussed above. To this end, itshould be appreciated that the hook platform 280 may be formed atvarious angles relative to the longitudinal axis of the bone plate 32 sto be received at selected positions on the ring of the C1 vertebra. Theplatform 280 may be provided with a retaining groove 282 and a hole 284retaining a cable (not shown) which may be extended about the throughthe hole 284, about the platform 280 along the retaining groove 282, andabout the ring of the C1 vertebra to hold the platform 280 in place onthe ring.

Referring now to FIGS. 31A and 31B, another embodiment of a pair of boneplate 32 t and 32 tt constructed in accordance with the inventiveconcepts disclosed herein is illustrated. The bone plates 32 t and 32 ttare identical in construction with the exception that the bone plate 32tt is a mirror image of the bone plate 32 t. Therefore, only the boneplate 32 t will be described in detail below. The bone plate 32 t isintended to fuse or stabilize multiple vertebrae, more specifically theC1 and C2 vertebrae. The bone plate 32 t is configured and dimensionedto extend along the posterior side of at least the C1 vertebra and theC2 vertebra, and particularly, the bone plate 32 r is configured toextend from a posterior ring 290 of a C1 vertebra 292 to a lamina 294 ofa C2 vertebra 296. It will be appreciated that the length of the boneplate 32 t may be varied depending on the number of vertebrae to bestabilized beyond the C2 vertebra.

The bone plate 32 t has an upper surface 298 and a lower surface 300.Like the bone plates described above, the lower surface 300 can beprovided with a textured surface such that described above in referenceto FIG. 4B which may include a variety of geometric shapes and/orprotrusions, such as spikes, or other features, such as ridges, posts,pockets, or be treated such as bead blasted or acid etched to enhanceits grip on the vertebral body.

The bone plate 32 t has a spacer portion 302 having a first end 304 anda second end 306. The longitudinal length of the spacer portion 302generally corresponds to the distance between the ring 290 of the C1vertebra 292 and the lamina 294 of the C2 vertebra 296.

A ring engaging portion 308 extends from the first end 304 of the spacerportion 308. The ring engaging portion 308 is configured to extend alongand conform to at least a portion of the ring 290 of the C1 vertebra292. More specifically, the ring engaging portion 308 has an arcuateprofile such that the ring engaging portion 308 substantially conformsto the contour of the ring 290 of the C1 vertebra 292. The ring engagingportion 308 has a width such that a plurality of holes 310 may be formedin the ring engaging portion 310 in such a way that at least two holesare positionable over the posterior side of the ring 290 of the C1vertebra 292. The holes 310 may be threaded or non-threaded similar tothe holes 56 and 76 discussed above to receive an attachment member,such as attachment members 34.

A lamina engaging portion 312 extends from the second end 306 of thespacer portion 302. The lamina engaging portion is configured to extendalong and conform to a portion of the posterior side of the C2 vertebra296, e.g., the lamina, the lateral mass, or a combination of the laminaand the lateral mass. As illustrated in FIGS. 31A and 32B, the laminaengaging portion 312 has a flatter profile than the ring engagingportion 308 so that the lamina engaging portion 312 substantiallyconforms to the contour of the lamina 294 of the C2 vertebra 296. Thelamina engaging portion 312 has a width such that a plurality of holes314 are formed in the lamina engaging portion 312 in such a way that atleast two holes are positionable over the lamina 294 of the C2 vertebra296. The holes 312 may be threaded or non-threaded similar to the holes56 and 76 discussed above to receive an attachment member, such asattachment members 34.

In one exemplary embodiment, the spacer portion 302 has a width that isless than the width of the ring engaging portion 308 and the width ofthe lamina engaging portion 312 so as to define a notch or window 316along an inside edge of the bone plate 32 t. The window 316 allowsdirect visualization of the central canal, as well as facilitatesidentifying the difference between the bone plate 32 r and 32 rr.

The holes 310 and 314 extend through the bone plate 32 r from the uppersurface 298 through the lower surface 300. The holes 310 and 314 may beentirely perpendicular to the plane of the bone plate 32 t, or may beoffset in the general direction which screw angulation is desired. Forexample, the holes 310 and 314 may be laterally outwardly angled, e.g.,at an angle of approximately 10 to 30 degrees of lateral outwardangulation.

The holes 310 are dimensioned and arranged relative to one another sothat more than one of the holes 310 are positionable or alignable overthe ring 290 of the C1 vertebra 292 to define a plurality of fixationpoints to the C1 vertebra 292, and the holes 314 are dimensioned andarranged relative to one another so that more than one of the holes arepositionable or alignable over the lamina 294 of the C2 vertebra 296 todefine a plurality of fixation points to the C2 vertebra 296. The holes310 and 314 may be arranged in a variety of ways to provide multiplepoints of fixation.

The bone plate 32 t and the holes 310 and 314 are shown to be sized andspaced is so that at least two of the holes 310 and 314 are positionableover each vertebra to which the bone plate 32 t is to be coupled(considering one side of the spine only and depending on the particularvertebra to which the plate is coupled). Those of ordinary skill in theart will understand that sizing and spacing of the holes 302 may bevaried to achieve a desired number of fixation points. By way ofexample, the holes 310 and 314 may have a diameter to accommodate ascrew having an outer diameter in a range from about 1.5 mm to about 3.0mm.

Like the holes 56 and 76 described above, the holes 310 and 314 areshown to be threaded to receive one of the attachment members 34 a.Again, those skilled in the art will appreciate that any threadconfiguration may be used, including variable angle locking threads, orthe holes 310 and 314 may even be non-threaded or smooth. Also, theholes 312 and 314 may be may be provided with flanges, as describedabove, to limit the extent of insertion of the attachment members 34.

Referring now to FIGS. 32A and 32B, another embodiment of a pair of boneplate 32 u and 32 uu constructed in accordance with the inventiveconcepts disclosed herein is illustrated. The bone plate 32 u and 32 uuare identical in construction with the exception that the bone plate 32uu is a mirror image of the bone plate 32 u. Therefore, only the boneplate 32 u will be described in detail below. The bone plate 32 u isintended to fuse or stabilize multiple vertebrae, more specifically theC1 and C2 vertebrae. To this end, the bone plate 32 u is configured anddimensioned to extend along the posterior side of at least the C1vertebra and the C2 vertebra. More specifically, the bone plate 32 u isconfigured to extend from the posterior ring 290 of the C1 vertebra 292to a juncture of the lamina 294 and spinous process 320 of the C2vertebra 296. It will be appreciated that the length of the bone plate32 u may be varied depending on the number of vertebrae to bestabilized.

The bone plate 32 u is similar to the bone plate 32 t in constructionand function, except that the bone plate 32 u includes a translaminaengaging portion 322 rather than a lamina engaging portion 312. Thetranslamina engaging portion 322 is configured to extend along andconform to at least a portion of the lamina 296, a junction 324 of thelamina 296 and the spinous process 320, and the spinous process 320. Thetranslamina engaging portion 322 has a lamina portion 326 and a spinousprocess portion 328 which are angled relative to one another to define ajunction portion 330. The translamina engaging portion 322 has a widthsuch that a plurality of holes 332 are formed in the translaminaengaging portion 322 so that at least two holes are positionable overthe combined area of the lamina 296 and the spinous process 320. In oneembodiment, the translamina engaging portion 322 has at least one hole332 a located through the bone plate 32 u at the junction portion 330and oriented in such a way as to permit translaminar screw placementwhen the translamina engaging portion 322 is positioned on the lamina296 and spinous process 320.

Referring now to FIGS. 33A and 33B, another embodiment of a bone plate32 v constructed in accordance with the inventive concepts disclosedherein is illustrated. The bone plate 32 v is intended to fuse orstabilize multiple vertebrae, more specifically the C1 and C2 vertebrae.To this end, the bone plate 32 v is configured and dimensioned to extendalong the posterior side of at least the C1 vertebra 292 and the C2vertebra 296. More specifically, the bone plate 32 v is configured toextend from the posterior ring 290 of the C1 vertebra 292 to each lamina294 of the C2 vertebra 292. It will be appreciated that the length ofthe bone plate 32 v may be varied depending on the number of vertebraeto be stabilized.

The bone plate 32 v has an upper surface 338 and a lower surface 340.Like the bone plates described above, the lower surface 338 can beprovided with a textured surface such that described above in referenceto FIG. 4B which may include a variety of geometric shapes and/orprotrusions, such as spikes, or other features, such as ridges, posts,pockets, or be treated such as bead blasted or acid etched to enhanceits grip on the vertebral body.

The bone plate 32 v has a spacer portion 342 having a first end 344 anda second end 346. The longitudinal length of the spacer portion 342generally corresponds to the distance between the ring 290 of the C1vertebra 292 and the laminae 294 of the C2 vertebra 296.

A ring engaging portion 348 extends from the first end 344 of the spacerportion 348. The ring engaging portion 348 is configured to extend alongand conform to at least a portion of the ring 290 of the C1 vertebra292. More specifically, the ring engaging portion 348 has an arcuateprofile such that the ring engaging portion 348 substantially conformsto the contour of the ring 290 of the C1 vertebra 292. The ring engagingportion 348 has a width such that a plurality of holes 350 are formed inthe ring engaging portion 348 in such a way that at least two holes arepositionable over the posterior side of the ring 290 of the C1 vertebra292. The holes 350 may be threaded or non-threaded similar to the holes56 and 76 discussed above to receive an attachment member, such asattachment members 34.

A first lamina engaging portion 352 extends from the second end 346 ofthe spacer portion 342, and a second lamina engaging portion 354 extendsfrom the second end 346 of the spacer portion 342. The first and secondlamina engaging portions 352 and 354 extend from the spacing portion 342as to define a notch 356 for receiving the spinous process 320 of the C2vertebra. Each of the first and the second lamina engaging portions 352and 354 has a flatter profile than the ring engaging portion 348 so thatthe lamina engaging portions 352 and 354 substantially conform to thecontour of the respective laminae 294 of the C2 vertebra 296. The laminaengaging portions 352 and 354 each has a width such that a plurality ofholes 358 are formed in the lamina engaging portions 352 and 354 so thatat least two holes are positionable over each of the lamina 294 of theC2 vertebra 296. The holes 358 may be threaded or non-threaded similarto the holes 56 and 76 discussed above to receive an attachment member,such as attachment members 34.

Referring now to FIGS. 34A-34C, shown in another embodiment of a boneplate 32 w constructed in accordance with the inventive conceptsdisclosed herein. The bone plate 32 w includes a plate portion 360,having an upper surface 362, a lower surface 364, and a plurality ofholes 366 extending through the plate portion 360 from the upper surface362 to the lower surface 364. The plate portion 360 is configured toextend along the posterior side of at least one vertebra adjacent alateral mass or lamina of the vertebrae and the holes 366 are spacedsuch that a plurality of holes is positionable over the vertebra todefine a plurality of fixation points to the vertebra.

The bone plate 32 w further has a post 368 extending from the uppersurface 362 of the plate portion 360. The post 368 has an enlargedspherical head portion 370 which is received within a bushing 372 sothat the post 368 can poly-axial rotate with respect to the bushing 372.The bushing 372 is positioned an inner spherical cavity formed in a rodreceiving head 374. Alternatively, the post 368 may be formed integralwith the rod receiving head 374 to form a monolithic structure. Also, asillustrated in FIGS. 35A and 35B, the post may be formed has a separatestructure which is adapted to be connected to the plate portion 362 orone of the other bone plates described herein. In one version, a post368 a (FIG. 35A) may include a threaded shaft 386 and a spherical head388 with variable angle locking threads so that the post 368 a isconnectable to a bone plate and insertable into bone. In anotherversion, a post 368 b (FIG. 35B) may include only a spherical head 390with variable angle locking threads so that the post 368 b is onlyintended to be connected to a bone plate without providing fixation tobone.

Returning to FIGS. 34A-34C, the rod receiving head 374 has a centralpassage 376 in which an elongated rod 378 may be seated so as totransversely extend through the central passage 376. The rod 378 may beseated in a saddle 380 positioned about the bushing 372 and secured inthe rod receiving head 372 with a threaded locking cap 382 that isthreaded to the rod receiving head 374 to lock the rod 378 in place.

Exemplary embodiments of polyaxial screws include those described inInternational Patent Application No. PCT/US2008/070670, filed on Jul.21, 2008, entitled “Polyaxial Bone Fixation Element,” InternationalPatent Application No. PCT/US2006/015692, filed on Apr. 25, 2006,entitled “Bone Anchor with Locking Cap and Method of Spinal Fixation,”and International Patent Application No. PCT/CH1997/00236, filed on Jun.16, 1997, entitled “Device for Connecting a Longitudinal Support with aPedicle Screw,” the contents of which are hereby incorporated byreference in their entirety. It should be understood, however, that thebone plate 32 u is not intended to be limited to any particular type oflocking cap or polyaxial screw configuration.

The bone plates described above may be constructed of any suitablebiocompatible material which has the structural strength and durabilityto withstand the cyclical loading associated with long term fixation tothe spine. Materials which would be suitable for such applicationsinclude, but are not limited to, titanium, titanium alloys (e.g., TAN),steel alloys such as stainless steel, tantalum, polymers such as PEEK,reinforced plastics, allograft bone, and other materials that would besuitable in alternative embodiments, such as composites. When the boneplates are constructed of a polymeric material, the attachment membersmay be constructed of a like material whereby the attachments membersmay be secured to the bone plate after insertion by welding. The boneplates can further include one or more bone growth or fusion-promotingelements, such as bone, bone morphogenetic protein (BMP), demineralizedbone matrix (DBM), LIM mineralization proteins (LMP), osteogenic pastes,and so forth. It is understood that such fusion-promoting elements arewell known by those of ordinary skill in the art.

Although bone plates and the other components of the posterior vertebralplating system have been described herein, it should be understood thatthe bone plates may include other features as well. For example, thebone plates may include instrument holding features on the outer surfaceor in the outer edge for facilitating grasping or stabilizing of thebone plates with instruments, such as forceps. Any of the bone platesdescribed herein may be provided with ribs along the upper surface, theedges, or the bottom surface to strength and/or stiffen the bone plates.The bone plates may be foldable or hinged for MIS (minimally-invasivespine surgery) access. The bone plates may be configured to so that onebone plate portion can translate relative to another bone plate portionalong a longitudinal axis so that the length of the bone plate may becustomized. The bone plates may be made of a mesh material to enablebone plates to be formed of a desired stiffness and without pre-formedholes while still providing the ability to attach the bone plates toselected vertebrae at multiple, selected points per vertebra. The boneplates could be stackable to allow the user to determine the stiffnessand strength required for a specific patient.

A variety of kits can be provided that contain any one or morecomponents of any of the posterior vertebral plating system describedherein. The components of the kits may be configured the same ordifferently. For example, within a single kit, bone plates may beprovided that have different lengths, different radii of curvature, holenumbers and configurations, differing cross sectional geometries ofholes, and so on, depending for example on the type of procedure beingperformed by a surgeon, or on the particular anatomies of individualpatients. The kits may also be configured differently with respect towhich components of the system are included in the kits. For example, akit for fixation of vertebrae via their lateral masses may includeplates of different lengths, widths, curvature, contours, hole numbersand patterns, hole angles, hole shapes, and hole types (i.e., forreceiving locking or non-locking, variable or non-variable screws).

From the above description, it is clear that the inventive conceptsdisclosed and claimed herein are well adapted to carry out the objectsand to attain the advantages mentioned herein, as well as those inherentin the inventive concepts. While exemplary embodiments of the inventiveconcepts have been described for purposes of this disclosure, it will beunderstood that numerous changes may be made which will readily suggestthemselves to those skilled in the art and which are accomplished withinthe spirit of the inventive concepts disclosed and/or as defined in theappended claims.

What is claimed is:
 1. A posterior vertebral plating system, comprising:a plate having an upper surface, a lower surface, and a plurality ofholes extending through the plate from the upper surface to the lowersurface, the plate being configured to extend along the posterior sideof at least two vertebrae adjacent at least one lateral mass of each ofthe vertebra and the holes being spaced in such a way that a firstplurality of holes is positionable over the lateral mass of a firstvertebra to define a plurality of fixation points to the first vertebraand a second plurality of holes is positionable over the lateral mass ofa second vertebra to define a plurality of fixation points to the secondvertebra, and a plurality of attachment members insertable through theholes of the plate and into the lateral mass of a corresponding vertebrato fix the plate to the vertebra, in which the plate has a first nodeportion that includes a node protruding laterally relative to alongitudinal direction of the plate and a second node portion thatincludes a node protruding laterally relative to the longitudinaldirection of the plate and that is connected to the first node portionby a recess, the first plurality of holes being located on the firstnode portion and the second plurality of holes being located on thesecond node portion, in which the holes are arranged in at least twolongitudinal rows of holes, the holes of one longitudinal row of holesbeing staggered relative to the holes of the other longitudinal row ofholes, each of the first plurality of holes and the second plurality ofholes including one node hole that is located on the node and belongs tothe one longitudinal row of holes and two bottom holes that belong tothe other longitudinal row of holes, the one node hole and the twobottom holes being arranged in a triangular pattern, and the spacingbetween each of the one node hole and the two bottom holes being equal,and in which the spacing between adjacent bottom holes of the firstplurality of holes and the second plurality of holes is greater than thespacing between the node hole and the bottom holes of the firstplurality of holes and the spacing between the node hole and the bottomholes of the second plurality of holes.
 2. The posterior vertebralplating system of claim 1, in which each of the holes has an axis, inwhich the holes have a plurality of columns of threads spaced apart todefine a plurality of non-threaded recesses, and in which at least oneof the columns of threads of one of the holes of a pair of laterallyadjacent holes intersects a line extending between the axes of the holesof the pair of laterally adjacent holes.
 3. The posterior vertebralplating system of claim 2, in which at least one of the columns ofthreads of each of the holes of a pair of laterally adjacent holesintersects a line extending between the axes of the holes of the pair oflaterally adjacent holes.
 4. The posterior vertebral plating system ofclaim 1, in which the holes have a plurality of columns of threadsspaced apart to define a plurality of non-threaded recesses, and inwhich the plate further includes a flange extending between adjacentcolumns of threads of at least one hole near the lower surface of theplate in such a way that the flange impedes the attachment members frombeing driven entirely through the hole.
 5. The posterior vertebralplating system of claim 1, in which the holes have a plurality ofcolumns of threads spaced apart to define a plurality of non-threadedrecesses between adjacent columns of threads, and in which the platefurther includes a flange extending between adjacent columns of threadsnear the lower surface of the plate in such a way that the flangeimpedes the attachment members from being driven entirely through thehole.
 6. The posterior vertebral plating system of claim 1, in which theplate has a perimeter edge extending between the upper surface and thelower surface, and in which the perimeter edge is configured tosubstantially conform to the contour of the holes of the plate.
 7. Theposterior vertebral plating system of claim 1, in which the plate has alongitudinal edge, and in which the plate has a rod portion formed alongthe longitudinal edge of the plate.
 8. The posterior vertebral platingsystem of claim 7, further comprising a lamina connector having a plateportion and a rod engaging portion, the plate portion positionable overa lamina of a vertebra when the rod engaging portion is engaged with therod portion of the plate and the plate is connected to the vertebrae. 9.The posterior vertebral plating system of claim 7, further comprising acrosslinking connector including a rod portion and a rod engagingportion formed on each of the rod portion, the rod extendable from oneside of a vertebra to an opposing side of the vertebra when one of therod engaging portions is engaged with the rod portion of the plate andthe plate is connected to the vertebra.
 10. The posterior vertebralplating system of claim 7, in which the rod portion extends beyond atleast one end of the plate.
 11. The posterior vertebral plating systemof claim 1 in which the plate has an outer longitudinal edge, and inwhich the plate further has a bone graft ridge extending upwardly andoutwardly from the outer longitudinal edge of the plate so as define apocket beneath the bone graft ridge in which biologic material may bepacked.
 12. The posterior vertebral plating system of claim 1, in whichthe plate has an inner longitudinal edge and an outer longitudinal edge,and in which the plate has a pair of flanges extending downwardly fromlower surface thereof along the inner longitudinal edge and the outerlongitudinal edge so as to define a pocket in which biologic materialmay be packed.
 13. The posterior vertebral plating system of claim 1, inwhich the plate includes a first plate portion and a second plateportion, and in which the first plate portion is pivotally connected tothe second plate portion.
 14. The posterior vertebral plating system ofclaim 13, in which the first plate portion is longitudinally alignedwith the second plate portion.
 15. The posterior vertebral platingsystem of claim 1, in which the plate has the greatest width at alocation of the node and has the smallest width at a location of therecess.
 16. A posterior vertebral plating system, comprising: a platehaving an upper surface, a lower surface, and a plurality of holesextending through the plate from the upper surface to the lower surface,the plate being configured to extend along the posterior side of atleast two vertebrae adjacent at least one lateral mass of each of thevertebra and the holes being spaced in such a way that a first pluralityof holes is positionable over the lateral mass of a first vertebra todefine a plurality of fixation points to the first vertebra and a secondplurality of holes is positionable over the lateral mass of a secondvertebra to define a plurality of fixation points to the secondvertebra, and a plurality of attachment members insertable through theholes of the plate and into the lateral mass of a corresponding vertebrato fix the plate to the vertebra, in which the plate has a first nodeportion that includes a node protruding laterally relative to alongitudinal direction of the plate and a second node portion thatincludes a node protruding laterally relative to the longitudinaldirection of the plate and that is connected to the first node portionby a recess, the first plurality of holes being located on the firstnode portion and the second plurality of holes being located on thesecond node portion, in which the holes are arranged in at least twolongitudinal rows of holes, the holes of one longitudinal row of holesbeing staggered relative to the holes of the other longitudinal row ofholes, each of the first plurality of holes and the second plurality ofholes including one node hole that is located on the node and belongs tothe one longitudinal row of holes and two bottom holes that belong tothe other longitudinal row of holes, the one node hole and the twobottom holes being arranged in a triangular pattern, and the spacingbetween each of the one node hole and the two bottom holes being equal,and in which the plate has the greatest width at a location of the nodeand has the smallest width at a location of the recess.